Conventional fiber optic cables comprise optical fibers that conduct light which is used to transmit voice, video, and data information. An optical ribbon includes a group of optical fibers that are coated with a ribbon common layer, which common layer may be of the ultraviolet (UV) light curable type. Typically, such a ribbon common layer (also known as a matrix) is extruded about a group of individually colored optical fibers that have been arranged in a planar array, and is then irradiated with a UV light source that cures the ribbon common layer. The cured ribbon common layer protects the optical fibers and generally aligns the respective positions of optical fibers in the planar array. Optical fiber ribbons can be connected to multi-fiber connectors, for example, MTP® brand multi-fiber connectors. MTP® connectors can be used in LAN applications, for example, data centers and parallel optics interconnects between servers.
Conventional networking solutions that utilize a 12-fiber MTP® connector assembly, for example, are configured in a point to point system. One MTP® connector is used for all of the fibers to be connected in a given 12-fiber cable. One conventional method of maintaining fiber polarity, i.e., based on a given fiber's transmit to receive function in the system, across such a connector assembly is achieved by flipping fiber orientation in one end of the assembly just before entering the MTP® connector. Such flipped orientation is maintained, for example, by an epoxy plug. Alternatively, “A” and “B” type break-out modules have been used, where the fiber pairs have their orientation reversed (also referred to as “flipped”) in the “B” module relative to the orientation in the “A” module.
Typically, transmit/receive pairs of fibers within an array-style connector such as an MTP® connector are arranged in so that the two fibers of a given pair are immediately adjacent each other within the connector. Fiber polarity is addressed by organizing and/or flipping the individual fiber connections at the other end of the MTP® connector assembly. The immediate fiber pairs are thus routed to multi-fiber or single-fiber connectors. In a system utilizing an “A” and “B” type module approach, the fibers within each transmit/receive part of the “B” module are flipped with respect to those in module “A” to address, or correct for, fiber polarity.
MTP® connectors have keys extending from a side surface to mandate orientation when mating to another item, such as another MTP® connector. Also, MTP® connectors have either pins or openings for receiving pins disposed at the surface where the fibers terminate for precise alignment of the fibers. Conventionally, when two MTP® connectors are mated, they are mated key up to key down, using one MTP® connector with pins and another with openings.
U.S. Pat. No. 6,758,600 discloses optical interconnection modules and related assemblies that provide certain useful improvements on the above structures. For example, the patent discloses an optical interconnection module wherein fiber pairs, which may extend from an array-style connector, are arranged so that at least one transmit/receive pair is formed of fibers not immediately adjacent each other within the array-style connector. Also, assemblies are disclosed wherein key positions are not reversed (either both up or both down) across connectors but wherein fiber paths are maintained across the assemblies.
Although the devices and assemblies of U.S. Pat. No. 6,758,600 work well for their intended applications, the multiple mating parts of the assemblies and systems require that various different parts be kept in stock. Thus, for some applications, it would be useful to have assemblies and systems having fewer and more uniform parts.